Based on facts, either observed and verified firsthand by the reporter, or reported and verified from knowledgeable sources.

Newsweek AI is in beta. Translations may contain inaccuracies—please refer to the original content.

The U.S. State Department on Sunday issued a “worldwide caution” alert for Americans traveling abroad, after President Donald Trump announced the U.S. had struck three nuclear sites in Iran.

Why It Matters

Trump on Saturday night announced what he called a “very successful” attack on three sites in Iran, directly inserting the U.S. into Israel’s conflict with Iran.

U.S. Defense Secretary Pete Hegseth said the strikes delivered a “final blow” to Iran’s nuclear program, though a senior Israel official has told Newsweek that it was not known if it is “fully annihilated.” American officials have long been concerned Iran was working to develop nuclear weapons. Iran says its program is peaceful and focused on energy production.

Iran has hit out at the U.S. for crossing “a very big red line,” but Trump has warned of has warned of additional strikes if Tehran retaliates.

An American Airlines Embraer E175LR airplane approaches Ronald Reagan Washington National Airport for a landing as American flags at the Washington Monument fly on June 19, 2025 in Washington, DC. An American Airlines Embraer E175LR airplane approaches Ronald Reagan Washington National Airport for a landing as American flags at the Washington Monument fly on June 19, 2025 in Washington, DC. Kevin Carter/Getty Images

What To Know

“The conflict between Israel and Iran has resulted in disruptions to travel and periodic closure of airspace across the Middle East,” the department said in a notice on its website on Sunday.

“There is the potential for demonstrations against U.S. citizens and interests abroad. The Department of State advises U.S. citizens worldwide to exercise increased caution.”

Global airlines were weighing how long to pause flights to the Middle East after the U.S. struck Iran, Reuters reported. Flights to destinations including Dubai, Doha and Riyadh have been cancelled in recent days.

Flight tracking website FlightRadar24 shows airlines were not flying above Iran, Iraq, Syria and Israel on Monday.

Meanwhile, the Department of Homeland Security issued a National Terrorism Advisory System Bulletin on Sunday, warning that the “ongoing Iran conflict is causing a heightened threat environment in the United States.”

What People Are Saying

Secretary of State Marco Rubio said on CBS News’ Face the Nation on Sunday: “We’ll impose costs on Iran if they attack American personnel, whether they do it directly, or whether they do it through some of these proxies that they try to hide behind.”

He added: “Let’s hope they don’t choose that route. Let’s all hope that they actually decide, OK, let’s go negotiate, because we want a diplomatic and peaceful solution.”

President Donald Trump wrote on Truth Social on Saturday: “ANY RETALIATION BY IRAN AGAINST THE UNITED STATES OF AMERICA WILL BE MET WITH FORCE FAR GREATER THAN WHAT WAS WITNESSED TONIGHT.”

Iranian Foreign Minister Seyed Abbas Araghchi wrote on X on Sunday: “The United States, a permanent member of the United Nations Security Council, has committed a grave violation of the UN Charter, international law and the NPT by attacking Iran’s peaceful nuclear installations. The events this morning are outrageous and will have everlasting consequences. Each and every member of the UN must be alarmed over this extremely dangerous, lawless and criminal behavior. In accordance with the UN Charter and its provisions allowing a legitimate response in self-defense, Iran reserves all options to defend its sovereignty, interest, and people.”

What’s Next

The State Department has urged U.S. citizens to read the travel advisory, county information and recent security alerts when planning travel.